Self-Sensitized and Reversible O₂ Reactivity with Bisphenalenyls for Simple, Tunable, and Multicycle Colorimetric...

Area of Science:

• Materials Science
• Chemical Sensing
• Photochemistry

Background:

• Accurate monitoring of molecular oxygen (O2) is crucial across various applications.
• Existing colorimetric O2 sensors often require costly additives and complex setups.
• Developing simple, cost-effective, and robust colorimetric O2 detection methods remains a challenge.

Purpose of the Study:

• To introduce bisphenalenyls (PQPLs) as single-component colorimetric sensors for molecular oxygen (O2).
• To investigate the mechanism of PQPLs' self-sensitizing photooxygenation and their conversion to aromatic endoperoxides (EPOs).
• To evaluate the performance of polymer-supported PQPL films for practical O2 sensing applications.

Main Methods:

• Synthesis and characterization of bisphenalenyls (PQPLs).
• Investigation of PQPL photooxygenation kinetics and mechanism, including singlet oxygen generation.
• Fabrication and testing of polymer-supported PQPL films (PTMSP) for colorimetric O2 detection.
• Assessment of sensor stability, reusability, and limit of detection.

Main Results:

• PQPLs function as the sole active component for colorimetric O2 sensing via conversion to EPOs.
• PQPLs exhibit self-sensitizing reactivity, generating and binding singlet oxygen without external photosensitizers.
• O2 sensitivity can be tuned by modifying PQPL substituents.
• Polymer-supported PQPL films show a rapid, visible color change (<5 ppm O2 detection limit) and excellent stability over multiple cycles.

Conclusions:

• Bisphenalenyls offer a novel, simple, and cost-effective platform for colorimetric molecular oxygen (O2) sensing.
• The developed PQPL-based sensors are robust, reusable, and suitable for printable applications.
• These materials hold potential as "intelligent" inks for developing advanced O2 detection systems.